Reposition Bellwire README for AI-native founders

[xwchris]

What changed

• leads with Bellwire as an AI-first iPhone project radar for indie hackers and AI-native founders
• explains the cross-project revenue, deployment, incident, and Agent-run pain before technical architecture
• adds a three-step Agent-first setup flow and a copyable integration prompt
• replaces the old light README screenshots with the current native dark screenshots from bellwire.app
• keeps Private delivery, deployment choices, licensing, architecture, and API documentation intact

Why

The previous README accurately documented the implementation but opened as notification infrastructure. It did not make the target user, founder pain, AI-first setup, or immediate product value clear enough.

Validation

• GitHub GFM rendering API
• all three dark screenshot URLs return HTTP 200
• App Store and product-film links return HTTP 200
• every referenced local documentation path exists
• git diff --check